Oil-burner



y 1952 E. SCHWANDER 3,033,270

OIL-BURNER Filed Dgc. 24, 1959 United States Patent 3,033,270 OIL-BURNER Erwin Schwander, Reichsholfen-Usines, France, assignor to Societe dEtude dc Vehicules S.E.V., Reichshoflen- Usines, France Filed Dec. 24, 1959, Ser. No. 861,876 Claims priority, application France Jan. 12, 1959 3 Claims. (Cl. 158--1.5)

The present invention relates to an oil-burner. The US. Patent No. 2,440,491, dated April 27, 1948, discloses an oil-burner wherein, according to a preferred embodiment, only a fraction of the combustion air is fed in the same direction as the stream of fuel, while the remainder of said air fed in the opposite direction, i.e. in countercurrent relationship with the fuel, inside the mixing chamber of the burner, with a 'view to ensure, thereby, an intimate mixture of the air with the fuel and the flame.

It is, therefore, one object of the present invention to provide an oil-burner which, in addition to the features of the known burner has further novel features. It has been found, in fact, that, in practice, the most favorable conditions are obtained when the second or remaining fraction of air is not introduced in counter-current relationship with the fuel directly into the mixing chamber, but is admixed with the fuel and the main or first fraction of the air in the flame by means of a deflecting plate capping the flame, the second fraction of the air being preferably preheated underneath the deflecting plate by an annular flame surrounding the latter, the combustion of which said second fraction it is to further.

It is another object of the present invention to provide an oil-burner wherein the combustion air is subdivided, before it enters the burner, into two streams, one of which enters the burner in the same direction as the fuel, so as to form with the latter at the outlet of the burner nozzle, a mixture which burns incompletely and which is directed, after ignition and with a view to obtain an intimate mixture of its components, towards a deflecting plate, while the other fraction of the air stream enters the burner in counter-current relationship with the fuel, so as to be admixed with the first mixture and to terminate its combustion. The burner is characterized by the fact that this latter fraction of the combustion air is preheated, before it is admixed with the first mixture, in an auxiliary arrangement associated with the burner directly or otherwise, after which it is brought into proximity with the side of the deflecting plate opposed to that subjected to the impact of the first mixture.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which the only figure is a vertical diagrammatic section of the oil-burner designed in accordance with the present invention.

Referring now to the drawing, the oil burner comprises a main pipe 1 leading into the outer burner casing 1", consisting of an upper portion 1 and a lower portion 2', the pipe being adapted for feeding the total combustion air 13 to the burner, to be subdivided into the fractions or streams 14 and 15, before entering the operative zone of the burner. The main air fraction 14 enters the upper end of the burner and is subdivided at this point into two sub-fractions 16 and 17. The sub-fraction 16 passes through a burner shield 3 disposed in the upper portion 1' of the burner and is fed at this point, through the atomizing nozzle 4, with the total fuel output which is atomized into fine particles. The fraction 15 of the air is fed through a pipe 7 tapped off the main pipe 1 to feed into a pipe 8. A deflecting plate is provided at the end of the pipe 8, which comprises a two-part plate including, in practice, a frusto-conical ring secured to the upper 3,033,270 Patented May 8, 1962 "ice end of the pipe 8 and a flat or dished central section 5:" closing substantially the upper end of the pipe 8, while leaving between the outer edge of the central section 5" and the frusto-conical section 5 a comparatively narrow slot 9', so-that a small sub-fraction 18 of the fraction 15 of air fed by the pipe 8 may pass through the slot 9 and act on the fine particles of coke forming a deposit on the central section 5", either for burning the same or for carrying them along towards the flame. v

In addition a frusto-conical ring 10 is fitted over the pipe 8 with its smaller end, in such manner that its securing line is located slightly underneath air discharge ports 9 formed in the outer wall of the pipe 8, while the larger end of the ring 10 opens upwardly into proximity with the frusto-conical ring 5 forming a portion of the deflecting plate. The incorporation of this second ring 10 results in the formation of extremely short flames, which is essential for a proper operation of the burner.

A throttling member 11 may be fitted coaxially inside the pipe 8, so as to restrict the flow of air through the pipe 8 for the following purposes: the pipe 8 permits, in a favorable manner, the preheating of the air fraction 15 fed along the pipe 8. This pipe 8 is subjected by the combustion gases to very high temperatures and, consequently, it is advisable, even if it is made of a heat-resistant steel, to provide a cooling, as intensely as possible, for the pipe 8 by the air fraction 15. A cylindrical inner member 11, provided in the pipe 8, is used for this purpose, since, on the one hand, it cooperates in increasing the speed of the air fraction 15 and, on the other hand, it absorbs a fraction of the heat radiated inwardly by the tube 8 and restores it subsequently through convection to the air fraction 15. The pipe 8 is preferably connected by means of radial stays 8' or the like with the cylindrical, inner member 11, which remains at a comparatively low temperature during the operation of the burner and which defines jointly with the pipe 8 an annular chamber 11', to constitute an assembly 12.

A burner designed in accordance with the present invention produces a very short flame. The bell-shaped expanded portion 6 of the burner casing 2' defining chambet 6' forms part of the volume available to the flame. It should be remarked that the flame emerging from the chamber 6 shows no longer the properties of an oil-burner flame, but that of a gas flame. It is transparent and it radiates only to a limited extent.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

What I claim is:

1. In an oil-burner, the combination of an outer-burner casing having an upper portion and a lower portion and receiving combustion air, means feeding fuel into said burner casing, a first pipe feeding a main stream of said combustion air into said upper portion of said burner casing, a burner shield disposed concentrically in said upper portion of said burner casing and receiving a first fraction of said main stream of combustion air, said burner shield defining jointly with said burner casing an annular chamber for passing a second fraction of said main stream of combustion air, a deflecting plate disposed across for a portion of the width of said burner casing and spaced apart from and opposite said burner shield, to provide a passage for the flame caused by the combustion of said fuel with said first and second fraction of said combustion air, said burner shield being adapted to mix fuel injected therein with said first fraction of combustion air, a second pipe connected at one end with said first pipe and leading towards the bottom face of said deflecting plate to feed a branch stream of said combustion air over the edge of the latter and to mix with said fuel and said combustion air in said flame and to bring about a completion of said combustion, said deflecting plate comprising a central plate and a peripheral frustocone surrounding said central plate to define an annular gap therebetween and flaring outwardly towards said flame, one end of said second pipe opening into the inner periphery of said frusto-cone to feed a first portion of said branch stream towards the bottom face of said central plate and over the peripheral edge of the latter through said annular gap to mix with said combustion air and said fuel in said flame, thus to bring about completion of said combustion, and means for feeding a second portion of said branch stream along the outer surface of said frusto-cone to mix with said combustion air and said fuel in said flame which has passed the outer edge of said frusto-cone, to still enhance the completion of said combustion.

2. The oil-burner, as set forth in claim 1, wherein said second pipe is connected at one end with said first pipe and a heat exchanging pipe receiving the other end of said branch pipe, said heat exchanging pipe opening at one end into the inner periphery of said frusto-cone and facing at said end the bottom face of said central plate, said heat exchanging pipe having a plurality of peripheral ports spaced apart from said frusto-cone, and said heat exchanging pipe jointly with said ports constituting said means for feeding a second portion of said branch stream along the outer surface of said frusto-cone.

3. The oilburner, as set forth in claim 2, which includes a second frusto-cone surrounding said heat-exchanging pipe and engaging the latter at its smaller end along an annular line disposed beyond said ports in relation to said first-mentioned frusto-cone, said second frusto-cone defining a gap jointly with said first-mentioned frusto' cone and providing a passage for said second portion of said air branch stream.

References Cited in the file of this patent UNITED STATES PATENTS 1,818,082 Mott Aug. 11, 1931 2,081,612 Woodson May 25, 1937 2,440,491 Schwander Apr. 27, 1948 2,518,364 Owen Aug. 8, 1950 

